Will, Sussexoak, Ken:
Yes, what is a dap?
I too have read the terns "Major" and "Minor" in regard to purlins. I interpret it as follows:
Minor is another word for common purlin (smaller roof memnbers).
Major is found in a common rafter system when the span is so great that a single beefy (major) purlin runs the length of the building, halfway between eve and ridge and supports the common rafters perpendicularly in the center of their span.
As far as obviously pegged purlins in the CG frames I've seen, there is a single peg through the rafter where the purlins intersect... looks like one peg holing both purlins (lapped?)...unless they're really long purlins and span 2 or more bents!
You can look at this photo of the actual barn I'm refering to here:
http://i286.photobucket.com/albums/ll84/mainebarns/GrayCornerskyward.jpgBut, you'll have to zoom in to see the pegged areas.
These rafters are spaced like the others, about 3-4 feet O.C.
This barn is an old hand hewn frame from the early 1800s. 1820 the owners say.
Will, it would seem this CG system spans a significant time period of at least 6 decades. The latest CG frame I encountered is sawn stock (circular) and dates to 1880. Again, the owners say.
I'm planning to revisit these soon and take many close up pictures, especially of the roof details... what else should I photograph... one thing that comes to mind is sills/bottom plates, and what they did on this part of the wall.
the dovetailed purlin comment was just for the sake of conversation. I have not seen this. Someone (sussexoak?) was asking about tying things together so the purlins dont fall out. I thought a dovetail would be a good solution. Albeit a lot of work!!
I'm excited about what's happened w/ this thread. I knew when I saw this style of construction it was unusual. You guys have been a great help.
may the education continue
Don
